1. Field of the Invention
The present invention generally relates to clothing and apparel, specifically to stockings and hosiery, and more particularly to a sock having improved moisture absorption and dissipation characteristics imparted by the selective arrangement of folds or pleats formed using different types of cloth or stitching.
2. Description of Related Art
Many articles of modern apparel are designed with moisture control in mind. While moisture can be introduced by external means, such as a rain shower, the problem that often arises relates to moisture resulting from excessive sweating, such as during exercising or running. Loose clothing, for example, is generally preferred over tight clothing for these activities, if increased moisture evaporation and dissipation is desired. Certain fabrics (e.g., cotton) are also known to have superior wicking or cooling characteristics.
One area wherein moisture control can be particularly problematic is that surrounding the feet. Since air flow about the feet is drastically reduced when wearing shoes, excess moisture can easily build up. This excess moisture can be particularly uncomfortable under different conditions. A jogger in warm weather may feel oppressively hot and humid, or a snowskier in very cold weather may find that initial foot moisture is now contributing to colder feet. Socks provide some inherent wicking, and many different sock designs have been devised with moisture in mind.
Early moisture control socks just used hydrophobic (i.e., non-absorbent) yarns to prevent moisture buildup. These yarns were typically synthetic, e.g., nylon, acrylic, polypropylene, or polyester. More advanced moisture-wicking materials use two fabrics, one (hydrophobic) that draws moisture away from the skin, and another that conducts it to the surface for evaporation. The latter fabric is hydrophilic (i.e., moisture absorbent), such as cotton or wool. Sock liners can be used which are made of a wicking fabric only, leaving the moisture absorption to the outer sock.
It is also known to provide terry loops on the inner surface of various types of socks, particularly those referred to as sweatsocks. The terry loops not only provide a cushion for active sport participants, and thermal insulation properties, but further provide for some wicking away of perspiration from the foot of the wearer. In U.S. Pat. No. 3,793,851, a boot sock is disclosed having such terry loops, with additional fabric thickness in the heel portion to provide a more comfortable fit. An auxiliary terry yarn is knit in plated relationship with the main terry yarn, wherein the main and auxiliary terry yarns both wick moisture from the foot to an outer layer of the sock. The leg portion of the sock includes elastic yarns which help maintain the leg portion in intimate contact with the skin. A similar design in shown in U.S. Pat. No. 4,422,307.
Socks have been designed to conduct moisture from certain areas of the sock to other areas. As taught by U.S. Pat. No. 4,898,007, a sock may be constructed of a first zone at the toe wherein the yarn is predominantly hydrophilic, a second zone at the heel wherein the yarn is also predominantly hydrophilic, and a third zone at the instep wherein the yarn is predominantly hydrophobic. As a result of the wicking action, moisture is transferred from the heel and toe to the instep of the sock. The upper leg portion may also be hydrophobic.
In the moisture control sock described in U.S. Pat. No. 5,095,548, a body yarn is knit in successive courses throughout the leg and foot portions. Other yarns (hydrophobic and hydrophilic) are knitted in partial courses and in plated relationship, whereby moisture generated at the sole of the sock is similarly wicked to the instep for evaporation. The cuff and upper leg portions again have elastic sewn in to keep the sock held tightly against the leg.
The prior art also includes combinations of the foregoing moisture control features with other improvements, such as thermal-insulating materials, cushioning, and support materials. Additionally, footwear has been provided that includes specially designed socks as well as complementary shoes. In U.S. Pat. No. 5,353,524, a moisture management sock includes a wicking panel, and air circulation channels. A moisture management shoe is adapted to cooperate with the sock by using a moisture wicking inner liner. Another design using cooperating socks and shoes is shown in U.S. Pat. No. 5,511,323. In that design, the tongue of the shoe overlies a hydrophobic knit instep portion of the sock, and the tongue is perforated to facilitate evaporation.
In addition to the foregoing approaches which use different types of materials (predominantly hydrophobic or hydrophilic) for different panels or portions of the sock, another approach involves the use of specially knits. For example, U.S. Pat. No. 4,195,497 describes an aerated stocking in which regions are knitted with both a synthetic, hydrophobic (nylon) yarn and a moisture-absorbent (cotton) yarn. The knit design not only provides a greater surface area of the synthetic material on the exterior surface than on the interior surface, but additionally provides aeration using air flow interstices knitted in those regions.
All of the foregoing approaches are limited by the amount of surface area available for moisture evaporation. Moreover, none of the prior art stocking constructions provide any way of effectively increasing the surface area of the sock available for moisture evaporation, and so do not take full advantage of the principles of advection and diffusion to increase moisture dissipation. It would, therefore, be desirable to devise a sock construction which allowed increased air flow and moisture control. It would be further advantageous if the construction were amenable to different embodiments to allow for fashion alternatives.